Aspects of the geographical variations of naturally occurring 210Pb/210Po in permanent teeth of juveniles in the UK

Purpose: To study geographical variations in the level of naturally occurring 210Pb-supported 210Po in permanent teeth of juveniles in the UK. Materials and methods: Permanent teeth extracted from 278 juveniles for orthodontic purposes were obtained from 48 counties in the UK. 210Po activity concentration was measured on the outer enamel surface using TASTRAK (alpha)-particle-sensitive plastic track detectors. Results: Geometric mean±SE activity concentrations in teeth from urban, suburban and rural areas, excluding the high radon area of Devon, were 8.41 +0.25/-0.24, 7.76 +0.37/-0.35 and 7.20 +0.49/-0.46 Bq kg-1, respectively. Overall, there was no significant association between (alpha)-activity on the outer enamel surface of permanent teeth and proximity to the major UK motorways. However, when the data were considered with respect to the prevailing southwesterly wind on the western side of the UK, a statistically significant association with respect to donors living downwind (on the easterly side) of the motorways was found. This effect was greater for sections of the M5 and M6 motorways that traverse urban areas. 210Po levels in teeth were also associated with domestic radon concentration. This effect was comparable with that from traffic and urban pollution. Conclusions: Higher levels of 210Pb-supported 210Po are seen in permanent teeth of juveniles near sources of increased exposure in the UK. Inhalation uptake is an important pathway of exposure, especially with respect to domestic radon exposure. The results might be important in assessing integrated exposure to 210Po in the skeleton and consequent high linear energy transfer dose to bone marrow.